1. Field of the Invention
The present invention relates to a liquid discharge head and a liquid discharge apparatus using the same.
2. Description of the Related Art
A liquid discharge apparatus is used for applying a liquid such as an ink to a recording medium by a liquid discharge head to form an image on the recording medium. The liquid is stored in a liquid tank detachably installed in the liquid discharge head. The liquid is supplied to a subtank (hereinafter referred to as a liquid storage chamber) within the liquid discharge head, and the liquid stored in the liquid storage chamber is supplied to an element substrate provided with a discharge port. When the liquid is consumed, the liquid tank is replaced. A technique for detecting the presence or absence of the liquid has been proposed for notifying a user of the time to replace the liquid tank and has been put into practical use.
International Publication No. WO2012/121693 discloses a liquid discharge head provided with a liquid detection mechanism. The liquid detection mechanism has an electrode pair (fluid sensor) provided in the liquid discharge head. Current flows between electrodes when the electrode pair comes into contact with a liquid. When the liquid level in the liquid storage chamber becomes low, and any one of the electrode pair is separated from the liquid level, the voltage between the electrodes increases. The fluid sensor detects the liquid level on the basis of this principle to detect the situation that the liquid in the liquid tank has been consumed. The liquid discharge head also has an energy-generating element which generates energy for discharging the liquid. The energy-generating element and the electrodes are electrically connected to a body of a liquid discharge apparatus through a common electric contact portion. The liquid discharge head is further provided with a needle-like liquid communication pipe extending through an exterior portion of the liquid tank for taking out the liquid within the liquid tank. When the liquid tank is set at a predetermined installation position, the liquid communication pipe is caused to pass through the exterior portion of the liquid tank to supply the liquid to the liquid storage chamber through the liquid communication pipe.
When the liquid tank is replaced, there is a possibility that a part of the liquid in the liquid tank may leak out of the liquid tank. Specifically, when a used liquid tank is pulled out of the liquid communication pipe or when a new liquid tank is set to cause a liquid communication pipe to pass through the exterior portion of the liquid tank, there is a possibility that the liquid may leak out of a portion through which the liquid communication pipe passes and then attach to the liquid communication pipe. According to the liquid discharge head described in International Publication No. WO2012/121693, the liquid communication pipe is located above the electric contact portion, so that there is a possibility that the liquid attached to the liquid communication pipe may fall and attach to the electric contact portion to cause short circuit at the electric contact portion.